A construction crew unearthed lead-tainted soil along San Antonio Road, prompting a higher price tag for the city’s streetscape project.

Like homebuyers eyeing local real estate, the Los Altos City Council experienced a bit of sticker shock over the price of dirt last week.

The council unanimously approved an additional $118,000 Feb. 12 for the $1.1 million San Antonio Road streetscape, in part to cover the disposal of lead-tainted soil recently discovered by the project’s construction contractor. The development came on the heels of a Feb. 7 announcement from the city that construction on the project was halted temporarily as a result of the discovery.

Combined with $147,000 in available contingency funds included as part of the project’s initial budget in July, the additional money will finance the estimated $190,000 for contaminated soil disposal, $25,000 in revisions to five handicapped-accessible ramps and maintain the remaining $50,000 as contingency funds for the project. The $118,000 appropriation, according to a staff report, will be funded by gas-tax reserves.

“It is unfortunate that we have uncovered additional costs in this project,” Councilwoman Megan Satterlee said prior to her vote. “It’s always unfortunate when we uncover additional costs in a project. … I think, unfortunately, we are at a phase in this project where we are in construction, and construction right now is held up contingent upon us dealing with the hazardous soil removal issue.”

The staff report noted that disposal of the contaminated soil requires the use of a licensed hazardous waste landfill in the Central Valley at a cost of $116 per ton, $113 per ton more costly than clean dirt disposal at a local landfill. City staff estimated a worst-case scenario requiring the disposal of an estimated 1,366 tons of contaminated soil.

Public Works Director Jim Gustafson told the council that three of four locations within the project area have already been identified as having contaminated soil, while an additional 14 excavation sites were in the process of being tested.

In terms of public safety, test samples showed lead contaminants at 3 to 38 milligrams per liter. In general, lead contamination is considered a public health risk at 400 milligrams per liter, according to the staff report.

“We know very well from the First Street (streetscape) construction that if you pursue the change order, it adds incremental costs from a staff perspective and also from a project delay perspective – that generally boosts the cost of those change orders,” Satterlee noted. “It’s really incumbent upon us to make those design decisions in advance of approving a contract. Unfortunately, in this instance, we thought we had done that.”

The council rejected a separate item to fund an additional $144,000 to install stacked stone-faced columns as part of a visual screen along San Antonio Road and Parking Plaza 3. The cost of the columns was originally estimated at $35,000. A masonry subcontractor, however, returned with a higher quote than anticipated, “and some work details were inadvertently omitted from the original estimate,” according to the report.

The council opted to reinstate the installation of granite columns, approved in the original project.